Thread rolling machine



May 13, 1952 w. STERN THREAD ROLLING MACHINE 4 Sheets-Sheet 1 Filed July 19, 1949 INVENTOR.

- May 13,1952 w s I 2,596,962 I THREAD ROLLING MACHINE Filed July 19, 1949 v I I 4 Sheets-Sheet 2 y 1 2 w. STERN 2,596,962

THREAD ROLLING MACHINE 7 Filed July 19, 1949 4 Sheets-Sheet 5 Patented May 13, 1952 WilliamStern, Chicago, 111., assignor O I-lliIlQiS 17001 Works, Chicago, 11-1., a corporation-of Illinois 7 ApplicationJulysle, 1949, Se1' ialN05105A93i Y This inventionrelates toia thread rolling machine, and more particularly to a machine for rolling threads on' the shanks of -screwblanks;

It is an object of thisinvention'to multiply the screw :working capacity of thread forming or rolling'machines'or'mechanisms.

Amcre specific object of :theinvention is to provide, fora single -action thread :rolling machine, particularly a standard type of inclined "screw thread rolling machine; mechanisms by which that machine may -bef'converted into "a double acting thread rolling machine, thereby Jdoubling'the: rate of production or capacity of the machine.

Other-objects of the Iinventicniare to provide in a reciprocating type Ithread rolling machine or .mechanisin multiple, double acting thread rolling dies and screw feeding:andstartingmechanism precisely timed with irespect to the: reciprocations of the "multiple "thread irolling dies to control the feeding'of screw elements into the dies to start the screw in one direction into the dies on movement thereof in acne direction and to start the move'mentrof the screws into the dies in the opposite direction on opposite movement-aof the dies; to provide simplifieddirect feedin means for delivering the screw elements or assembled screw blank and washer units to the multiple dies under-the .control ot the combined starter and feeding mechanism, and to provide novel and improved means for driving the "screw starting orscrew starting and feedingmechahismtoprevent jamming of the machine on'improper positioning of "the screw element :cr blank 'in the -thread rolling dies.

Other *aiid'furthe'r objects and advantages of the :invehtion will :appear apparent from the iollowing description'when taken in connection with the accompanying drawings wherein:

Fig. -1 is a fragmentary :planview of a machine embodying the present'invention;

Fig. 2' is a view in generally vertical section taken substantially'along the-:line-l-l of Fig. 1;

r-Figu3 is a view in vertical section taken sub- -Fi'g.;-3 is an enlarged View in {geh'erallyvertical 2 c section taken-substantially alcong the line B' 8 of Figffi;

Figs. *9 to '15- inclusiveware diagrammatic :views in generally horizontal section through the multiple thread rolling :dies of the'i'starter-and' ifeed mechanismillustrating Kathe operation "thereof andzthetiming of the'mechanismy Fig.--16 is a iviewin elevation ora -typical :screw blank as delivered. to the thread rolling dies; and

Fig. -"17 is a view;similar toFig.,;16showing-"the enlargedthread ilOllBdOH the b'lank pf Fig; "16..

As: shown in it-he drawings, a machine which forms .one embodimentof the presentinvention comprises an inclined screw thread :rolling ana- 137 89;!3'19 ofiMarch 351, 19313110 which. is attached a plurality of additional "and "substitute vor :auxiliary'mechanisms by which the rate of production orcapacity f the" machine'mayrbe'doubled;

The above mentioned standard type of "thread rolling machineizcomprises a'i'base .orabody d; 3 rand-:8, inclined at' an 311818101 approximately 30 degrees fto athehorizontalwa hopper :(not

shown) .for receiving a mass of screw blanks, and 'a 'screwi blank sfeedsmechahism :(not shown) for discharging from "the hopper screw :blanks which are *delivered *to *a :transfervmechanism *(not shown) -byr a continuous.cinclined chute '(not shown) .'i That-transfer :mechanis'rh, which by this invention -applica-nt has eliminated, is

employed infsaid standa'rd type of thread rolling machine to carry and position the screw :between a pair of thread rollingvrdies into which it is pushed by :a starter finger. The continuous screw feeding -chutepthe transfer mechanism, and the-commonform -of starter finger of the standard machine are replaced by the following described additional substitute or auxiliarymechanisms by which the machine is conblock 26 is adjustably mounted-on and clamped to the standard die mounting block Bil-securedtand supported in the usual manner'on the depending forward end :pOIfiOH-Of the auxbaseeor body Mandate :statipha'ryfdiefl is-similarly adjust-ably mounted and clamped to a like die mounting block 32 mounted adjacent the die mounting block in longitudinally spaced relation and similarly supported or secured to the auxiliary base or body 4 upon that portion thereof which in a standard machine forms a shelf or support for the transfer mecha nism. The moving or reciprocating dies 22 and 24 are adjustably clamped to a die mounting bar or block 34 in the usual manner, but in end to end longitudinally spaced relation with a spacing block 35 inserted between the die blocks, the mounting block 34 being similar in form to the standard reciprocating die mounting block but having a longer die mounting recess therein to accommodate the twin dies 22 and 24. The die mounting block 34 is carried by and secured to the standard reciprocating bar 38 which is guided in the usual guideway formed by the auxiliary base or body 4, a gib 31 (Fig. 2) and a flange cover plate 39 secured thereto. The twin dies 22 and 24 are alike in every respect and the thread forming ribs or ridges of the dies are inclined in'the same direction with respect to the edges of the dies (see Fig. 3). The twin stationary dies 26 and 28 are also alike in every respect, the thread forming ridges or ribs thereof being similarly inclined in'the same direction.

The chute l4 comprises a pair of inclined, spaced bars having portions 38 and 40 (Fig. 7) extending substantially parallel to the path of reciprocation of the moving dies, and curved end portions 42 and 44 extending over the adjacent end edges of the stationary dies 26 and 28 and terminating substantially in the plane of the workingfaces of these dies. The chute bars are spaced apart a distance slightly greater than the diameter of the shanks of the screw elements so as to permit the free passage of the shanks therebetween as the screw elements gravitate down the chute, and at the same time support the heads of the screw elements. The end portions 42 and 44 of the chute bars are so tapered vertically that as the screws gravitate down the chute to the thread rolling dies, the heads of the screws finally rest upon the plane of the upper edges of the dies. The chute bars are so positioned at the lower ends that as the screws move down the tapered end edges of the section of the bars the shanks pass into the space between the die mounting blocks 30 and 32 and are guided and held against tilting movement in a direction lengthwise of the dies by the confronting faces of the die mounting blocks or the ends of the stationary dies.

The chute l4 also includes a cover bar 43 secured as by mounting straps 48 to the chute bars. This cover bar is provided at its lower end with a curved portion 50 concentric to the curved portions 42 and 44 and overlying the heads of the screws as they pass down and along the curved portions 42 and 44. Certain screws, the heads of which are of relatively large diameter compared with the diameter of the shanks of the screws, have a tendency to pile up in head-overlapping positions along the lower end of the portions 42 and 44 of the chute bars. This overlapping may cause the foremost screw element as it passes into the space between the complementary moving and stationary dies to be tilted with respect to the dies so that the head thereof does not lie flush upon the upper edge surfaces of the dies, as shown in Fig. 8. This both interferes with the feeding of the screws down the chute with the proper operation of the starter mechanism as will hereinafter be described, and with the proper working of the dies upon the shanks of the screw blanks. Accordingly, applicant provides for use with such screws a cover bar 46 which at its lower end is provided with a transverse finger 52 (Figs. 1 and 8) that extends over the space between the complementary moving and stationary dies and extends longitudinally of the dies so as to prevent tilting of the foremost screw blank as it moves into the dies by properly guiding the head of the screw blank.

. -The starter mechanism 54 (Fig. 4) comprises a finger 56 (Figs. 3, 4 and 6 to 15) in the form of a plate having a base portion 58 bolted to a slide bar 60. As shown best in Fig. 8, the slide bar 60 is guided in ways formed in laterally spaced upstanding portions 62 and 64 of the auxiliary base or body 4 so that the starter finger or plate 56 projecting upwardly from the slide bar extends between the complementary moving and stationary dies and moves parallel to the moving dies as the moving dies and slide bar 60 are reciprocated. The slide bar 60 is also slidably mounted upon an elongated rod 60 of an automatically releasable guide means or connection 68 including in addition to the rod 66 a coil spring 10 encircling rod 66 and interposed between the forward end of the slide bar 60 and a washer 12 held on the rod by a nut I4. The rod 66 at its inner end is threaded into theforward end of a reciprocating driving, or slide, bar 16 guided in the same ways as the bar 60'and serving to drive the slide 60 in a forward direction by abutting engagement with the slide bar 60 and-in the opposite or reverse direction through the rod and the spring 10. The bar 16 is provided adjacent its rear end with an upstanding bracket 78 secured to the forward end of a vertical slide bar 80 guided in vertical ways formed in a bracket 82 secured to the upstanding portion 64 of the auxiliary base or body 4 to the rear of the die mounting block 32. A driving block 83 is pivoted to the rear end of the vertical slide 80and it is received in a bifurcated block or yoke 84 of a drive lever 86 keyed to a drive shaft 88.

The rock shaft 88 is journaled in a boss 90 formed in the cover plate 39. The rock shaft is driven in a counter-clockwise direction, as seen in Fig. 3, by a starter slide drive cam 92 fastened to a drive shaft 94, cam 92 being engaged by a cam roller 96 mounted between the ends of a lever 98 pivoted at its lower end on a fixed bracket I00; The lever 98 drives the shaft 88 in a counterclockwise direction through a link or bar' I02 (Figs. 2 and 3) and a crank I04 on the shaft 88. On such counter-clockwise rotation of shaft 88 the starter slide 80 is retracted. The starter slide is advanced or moved forwardly by the action of a coil spring I06 secured at one'end to the upper end of the lever 98 and at the other end to a fixed pin I08 in the cover plate 39, the cam 92 determining the distance of advance movement of the starter slide.

The shaft 94 is one of the usual drive shafts of the standard type thread rolling machine and the starter slide drive cam 92 replaces the standard starter slide cam which in the standard machine holds the starter finger at rest in its rearward position during most of the cycle of reciprocation of the movable threadl rolling' die and advances it during the initial forward moveni'ent'o'f the movable thread rolling die and then 7 5 returns *to its normal I rear position while the tl'iread-relling die is stillmovin'g forwardly.

{n "the shaft -94 is also mounted the 'usual "drivegear-H-U which is driven by gear 112 on th'e mai-n -drive shaft "H 4, the gear H9 having =fiinr1ed'to" its face a 'pitma-n -l l-fi pivoted to the rear-"end of, and reciprocating the slide 33 which carries-the movable dies. The main drive shaft "H is driven inthe usual manner by an electric motor (not shown) through a belt it, Fig. 1, 'passing about a pulleyl'22 on the motor shaft -arrd a pulley l zfi on the sha'ft l l l.

'Wfeans -are -pro'v'ided for assisting the injectiono'f'each screw element, or each screw and washer assembly unit, into the threadrol-ling dies. This-means comprises apair of air nozzles l 2li and FZBfiFi'g; 7, coupled to'a connnon air pressure hos'e 1313, the air nozzles 4 25 and 23 being mounted in-any suitable manner to overthelower ehd of the chute portions 42 and and" to direct air pressure against the leading "screws'as the'yreach the lower end of the chute. "As 'each's'crew element readhes the end-of the "chute, as'se'enin li ig. 8, and approaches "thedies, it passes from-a sharply inclined teeding plane the plane of the upper edges-of the dies, as

:seen i-n said figure, and therefore the gravitaer finger when the end of "the chute is-uncovered "The operation of the "starter finger, which is also 'used- 'as'a gate to control the feeding of the "screwsdirectlyfromthe feeding chute It, is best shown in*Figs. 9 to For purposes of explaining this operation, let us assume that the'starter finger has been moved to its rearmost position, as seen inFig. 9, "by the engagement of the cam roller 96 with the high-point of the cam 92, and the movable dies 22 and '24have started to adyance forwardly, as indicated insai d figure. As the forward edge of the thread rollingdie 22 approaches Ttheirear end'of theista'tionary thread rolling die 26, the starter finger 56 is caused to moveiforwardly under the action of spring I06 i'a's'lth'eham roller 96 traverses the reducing-radius portion of the cam 92, this. movement -.o'f*the .movable die 22 and the starter Jfinger being illustrated-in Fig. 10. The starter finger moves for- "w'a'rdly just su'flicient 'to assure the injection of the shank of the screw between the die 22 and the die 26 so that the continued forward movement of the die 22 causes rolling of the thread on the shank of the screw and the screw in that rolling process forwardly traverses or rolls along the stationary die 25. The starter finger then remains at rest (roller 95 engaging a constant radius portion of cam 92) and is positioned to close the lower end of the screw chute until the movable thread rolling die approaches its forward limit of movement. At that time the starter finger again moves forwardly, as indicated in Fig. 11, as the roller 96 moves into a pleted and the threadrolling-dies immediately begin their rearward movement The starter finger now moves rearwardly, as illustratedin Fig. 13, along with the movable thread rolling "dies, as the roller '95- mov'es out of -the notch in 'thecam flg to insure the' inje'ction of the screw "shankmetween the rearwardly movin'g fthread rolling die -24"andthe rear stationary thread The starter finger moves rearthen remains at rest during-the continued "rearwardmovement of the thread rolling dies as' the 'rdller Stengages a constant radius portion- 0f the cam 92 and until the movable dies approach their rearward limitof movement. At tHis'time "the starter-finger again moves rearwar'dly; as i1- lustrated bythe arrow in Fig. -14, to uncover the chute "and allow the nextscrew -'e1emen't"at the lowerend of the chute to "pass into position "-in advance of the starter finger, as illustrated "in Fig." 1-5, at themoment that-the movable thread rolling dies ha-vecompleted their rearward movement.

'It should *be noted that if "forwardmovement of the starterfinger -56 is prevented by reasonof a mispositioned or tilted screw, i. -'e., one which has not completely cleared thescrew chute but has a partlYinginfrontbf the starter "finger, no harm will result because this "forward "movement of "the starter finger is caused only by the spring 10b. Therefore if the forward movement of the starter finger is prevented; cam roll-- er -98 "wi'llsimply not'fo'llow thesurface-of the starter slide control "cam 92 but will remain out of engagement with the cam. ."It should further beinoted" that if "the starter finger "is jammed "against "rearward movement, as by a misposi- "rearwardly with it along with the rod "66 at- "ta'ched thereto and thereby contract the "spring '10,; "the starter fingerii'iii remaining'stationary and-the rod *6 6 sliding through.

"Means is provided for assisting the discharge of the rolled screw,0r the finished 'screwa'nd washer assembly, from the movablethread rolling 'die 24 and the stationary-"die "28. Sincethe dies are inclined and reciprocate relatively in -an inclined plane, on the rearward movement of themovable dies, the "screws are carried uphill. The momentum-imparted to thescrews by the reciprocation and "rolling action of the dies cause the screw to be impelled from the stationary die 28 as it reaches "the upper *end'thereof, but in some instances the "screw may "drop back after having lost momentum and fall between the dies 24 and 26. The discharge means, preventing this falling back of the finished screw or finished screw and washer assembly, comprises an air nozzle I32, Figs. 1 and 7, coupled to a suitable source of air under pressure, which may be the same source as that which supplies the tube I30. This nozzle is so positioned at or adjacent the upper end of the stationary die 23 and is so oriented that the pressure of the air escaping therefrom imparts sufiicient momentum to the finished screw or finished screw and washer assembly after it has lost the momentum imparted to it by the action of the dies as to cause the screw or screw and washer assembly to drop into a discharge chute I34, Fig. l, by which the screw is directed into a receiving pan It will be apparent from the foregoing description that applicant has provided devices to multiply the screw working capacity of thread forming or rolling machines or mechanisms, in a single action thread rolling machine, particularly a standard type of inclined screw thread rolling machine, mechanisms by which that machine may be converted into a double acting thread rolling machine, thereby doubling the rate of production or capacity of the machine; ina reciprocating type thread rolling machine or mechanism multiple, double acting thread rolling dies and screw feeding and starting mechanism precisely timed with respect to the reciprocations of the multiple thread rolling dies to control the feeding of screw elements into the dies to start the screw in one direction into the dies on movement thereof in one direction and to start the movement of the screws into the dies in the opposite direction on opposite movement of the dies; a simplified direct feeding means for delivering the screw elements to the multiple dies under the control of the combined starter and feeding mechanism, and a novel and improved means for driving the screw starting or screw starting and feeding mechanism to prevent jamming of the machine on improper feeding or initial feeding of the screw element or blank into the thread rolling dies.

It will be obvious that changes may be made in the form, construction and arrangement of the parts Without departing from the spirit of the invention or sacrificing any of its advantages, and the right is hereby reserved to make all such changes as fairly fall within the scope of the following claims.

The invention is hereby claimed as follows:

1. A screw blank working apparatus including a stationary die having an elongated working surface provided with longitudinal groove forming ribs extending entirely along said working surface except for the blank feed opening medially thereof substantially the width of a blank, a movable die having longitudinal groove forming ribs and movable along said working surface, back and forth, from one side of said feed opening to the other side thereof, the trailing end thereof passing said medial opening at each movement thereof whereby a blank is thereby grooved at each side of said medial opening, an elongated straight line reciprocating feeder and means for reciprocating the same, said feeder being of a width less than the rib spacing of said dies, and the length of said feeder and the said means being so constructed that one end of said feeder passes said opening in pushing a blank to a groove rolling position between said stationary die and advancing movable die while the other end of said feeder holds the remaining blanks in said feed opening until further movement clears said opening for the feed of a second blank into the path of said other end of said feeder, whereupon reverse movement of said feeder pushes said second blank to groove rolling position at the other side of said medial opening for continued operation in a similar manner.

2. A screw blank working apparatus as claimed in claim 1, having means including air blast mechanism for continuously urging screw blanks against the holding surface of the feeder to assure positive feeding of the blanks into the path of movement of the pusher surfaces.

3. A screw blank working apparatus as claimed in claim 1, wherein the actuating mechanism for the feeder is positioned below the die units.

4. A screw blank working apparatus including a stationary die having an elongatedworking surface provided with groove forming ribs extending entirely along said working surface except for the blank feed opening medially thereof substantially the width of a blank, a movable die having groove forming ribs and movable along said working surface, back and forth, from one side of said feed opening to the other side thereof, the trailing end thereof passing said medial opening at each movement thereof whereby a blank is thereby grooved at each side of said medial opening, an elongated straight line reciprocating feeder and means for reciprocating the same, said feeder being of a width less than the rib spacing of said dies, and the length of said feeder and the said means being so constructed that one end of said feeder passes said opening in pushing a blank to a groove rolling position between said stationary die and advancing movable die while the other endof said feeder holds the remaining blanks in said feed opening until further movement clears said opening for the feed of a second blank into the path of said other end of said feeder, whereupon reverse movement of said feeder pushes said second blankto groove rolling position at the other side of said medial opening for continued operation in a similar manner.

\VILLIAMZ STERN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,584,264 Wilcox May 11, 1926 1,696,225 Blood Dec. 25, 1928 1,783,796 Kinney Dec. 2, 1930 2,343,798 Poupitch Mar. 7, 1944 2,509,056 Gartner May 23, 1950 

